package org.cloud.im.core.utils;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.UnsupportedEncodingException;
import java.nio.ByteBuffer;
import java.sql.Time;
import java.sql.Timestamp;
import java.util.Calendar;

/**
 * @Author: w.weidong.lin@abite.com
 * @Description: TODO
 * @Date: create in 2021/10/19 14:22
 */
public class BufferUtil {
    private static Logger log = LoggerFactory.getLogger(BufferUtil.class);

    public static byte read(ByteBuffer buffer) {
        return buffer.get();
    }

    public static int readUB2(ByteBuffer buffer) {
        int ret = buffer.get() & 0xff;
        ret |= (buffer.get() & 0xff) << 8;
        return ret;
    }

    public static int readUB3(ByteBuffer buffer) {
        int ret = buffer.get() & 0xff;
        ret |= (buffer.get() & 0xff) << 8;
        ret |= (buffer.get() & 0xff) << 16;
        return ret;
    }

    public static long readUB4(ByteBuffer buffer) {
        long ret = buffer.get() & 0xff;
        ret |= (long) (buffer.get() & 0xff) << 8;
        ret |= (long) (buffer.get() & 0xff) << 16;
        ret |= (long) (buffer.get() & 0xff) << 24;
        return ret;
    }

    public static int readInt(ByteBuffer buffer) {

        int i = buffer.get() & 0xff;
        i |= (buffer.get() & 0xff) << 8;
        i |= (buffer.get() & 0xff) << 16;
        i |= (buffer.get() & 0xff) << 24;
        return i;
    }

    public static float readFloat(ByteBuffer buffer) {
        return Float.intBitsToFloat(readInt(buffer));
    }

    /**
     * 8个字节
     *
     * @param buffer
     * @return
     * @author: wchao
     * 2017年1月23日 下午3:07:31
     */
    public static long readLong(ByteBuffer buffer) {
        return buffer.getLong();
    }

    public static double readDouble(ByteBuffer buffer) {
        return buffer.getDouble();
    }


    public static String readString(ByteBuffer buffer) {
        return readString(buffer, null);
    }

    public static String readString(ByteBuffer buffer, String charset) {
        if (!buffer.hasRemaining()) {
            return null;
        }
        //		String s = new String(data, position, length - position, charset);
        //		position = length;
        int length = buffer.limit() - buffer.position();
        String s = readString(buffer, length, charset);
        return s;
    }

    public static String readStringWithNull(ByteBuffer buffer, String charset) {

        if (!buffer.hasRemaining()) {
            return null;
        }
        int offset = -1;
        int position = buffer.position();
        int length = buffer.limit();
        boolean needPlus1 = true;
        for (int i = position; i < length; i++) {
            if (buffer.get(i) == 0) {
                offset = i;
                break;
            }
        }
        if (offset == -1) {
            needPlus1 = false;
            offset = buffer.limit();
            //			String s = new String(b, position, length - position);
            //			position = length;
            //			String s = new String(buffer.array());
            //			buffer.position(buffer.limit());
            //			return s;
        }
        if (offset > position) {
            //			String s = new String(b, position, offset - position);
            //			position = offset + 1;
            int bytelength = offset - buffer.position();
            String s = readString(buffer, bytelength, charset);

            if (needPlus1) {
                buffer.position(buffer.position() + 1);
            }

            return s;
        } else {
            //			position++;
            buffer.position(buffer.position() + 1);
            return null;
        }
    }

    /**
     * 读取指定长度的String
     *
     * @param buffer
     * @param length
     * @param charset
     * @return
     * @author: wchao
     * 2017年1月25日 下午12:12:07
     */
    public static String readString(ByteBuffer buffer, int length, String charset) {
        int bytelength = length;
        byte[] dst = new byte[bytelength];
        buffer.get(dst, 0, bytelength);
        String s = null;
        if (charset != null) {
            try {
                s = new String(dst, charset);
            } catch (UnsupportedEncodingException e) {
                log.error(e.toString(), e);
                s = new String(dst);
            }
        } else {
            s = new String(dst);
        }
        return s;
    }

    public static String readStringWithNull(ByteBuffer buffer) {
        return readStringWithNull(buffer, null);
    }


    public static Time readTime(ByteBuffer buffer) {
        move(6, buffer);
        int hour = read(buffer);
        int minute = read(buffer);
        int second = read(buffer);
        Calendar cal = getLocalCalendar();
        cal.set(0, 0, 0, hour, minute, second);
        return new Time(cal.getTimeInMillis());
    }

    public static java.util.Date readDate(ByteBuffer buffer) {
        byte length = read(buffer);
        int year = readUB2(buffer);
        byte month = read(buffer);
        byte date = read(buffer);
        int hour = read(buffer);
        int minute = read(buffer);
        int second = read(buffer);
        if (length == 11) {
            long nanos = readUB4(buffer);
            Calendar cal = getLocalCalendar();
            cal.set(year, --month, date, hour, minute, second);
            Timestamp time = new Timestamp(cal.getTimeInMillis());
            time.setNanos((int) nanos);
            return time;
        } else {
            Calendar cal = getLocalCalendar();
            cal.set(year, --month, date, hour, minute, second);
            return new java.sql.Date(cal.getTimeInMillis());
        }
    }


    public static void move(int i, ByteBuffer buffer) {
        buffer.position(buffer.position() + i);
    }

    public static void position(int i, ByteBuffer buffer) {
        buffer.position(i);
    }

    public static final void writeUB2(ByteBuffer buffer, int i) {
        buffer.put((byte) (i & 0xff));
        buffer.put((byte) (i >>> 8));
    }

    public static final void writeUB3(ByteBuffer buffer, int i) {
        buffer.put((byte) (i & 0xff));
        buffer.put((byte) (i >>> 8));
        buffer.put((byte) (i >>> 16));
    }

    public static final void writeInt(ByteBuffer buffer, int i) {
        buffer.put((byte) (i & 0xff));
        buffer.put((byte) (i >>> 8));
        buffer.put((byte) (i >>> 16));
        buffer.put((byte) (i >>> 24));
    }

    public static final void writeFloat(ByteBuffer buffer, float f) {
        writeInt(buffer, Float.floatToIntBits(f));
    }

    public static final void writeUB4(ByteBuffer buffer, long l) {
        buffer.put((byte) (l & 0xff));
        buffer.put((byte) (l >>> 8));
        buffer.put((byte) (l >>> 16));
        buffer.put((byte) (l >>> 24));
    }

    public static final void writeLong(ByteBuffer buffer, long l) {
        buffer.put((byte) (l & 0xff));
        buffer.put((byte) (l >>> 8));
        buffer.put((byte) (l >>> 16));
        buffer.put((byte) (l >>> 24));
        buffer.put((byte) (l >>> 32));
        buffer.put((byte) (l >>> 40));
        buffer.put((byte) (l >>> 48));
        buffer.put((byte) (l >>> 56));
    }

    public static final void writeDouble(ByteBuffer buffer, double d) {
        writeLong(buffer, Double.doubleToLongBits(d));
    }

    public static final void writeLength(ByteBuffer buffer, long l) {
        if (l < 251) {
            buffer.put((byte) l);
        } else if (l < 0x10000L) {
            buffer.put((byte) 252);
            writeUB2(buffer, (int) l);
        } else if (l < 0x1000000L) {
            buffer.put((byte) 253);
            writeUB3(buffer, (int) l);
        } else {
            buffer.put((byte) 254);
            writeLong(buffer, l);
        }
    }

    public static final void writeWithNull(ByteBuffer buffer, byte[] src) {
        buffer.put(src);
        buffer.put((byte) 0);
    }

    public static final void writeWithLength(ByteBuffer buffer, byte[] src) {
        int length = src.length;
        if (length < 251) {
            buffer.put((byte) length);
        } else if (length < 0x10000L) {
            buffer.put((byte) 252);
            writeUB2(buffer, length);
        } else if (length < 0x1000000L) {
            buffer.put((byte) 253);
            writeUB3(buffer, length);
        } else {
            buffer.put((byte) 254);
            writeLong(buffer, length);
        }
        buffer.put(src);
    }

    public static final void writeWithLength(ByteBuffer buffer, byte[] src, byte nullValue) {
        if (src == null) {
            buffer.put(nullValue);
        } else {
            writeWithLength(buffer, src);
        }
    }

    public static final int getLength(long length) {
        if (length < 251) {
            return 1;
        } else if (length < 0x10000L) {
            return 3;
        } else if (length < 0x1000000L) {
            return 4;
        } else {
            return 9;
        }
    }

    public static final int getLength(byte[] src) {
        int length = src.length;
        if (length < 251) {
            return 1 + length;
        } else if (length < 0x10000L) {
            return 3 + length;
        } else if (length < 0x1000000L) {
            return 4 + length;
        } else {
            return 9 + length;
        }
    }

    private static final ThreadLocal<Calendar> localCalendar = new ThreadLocal<Calendar>();

    private static final Calendar getLocalCalendar() {
        Calendar cal = localCalendar.get();
        if (cal == null) {
            cal = Calendar.getInstance();
            localCalendar.set(cal);
        }
        return cal;
    }

}
